1. Field of the Invention
The present invention relates to a liquid droplet jetting apparatus such as an ink-jet printing apparatus (ink-jet printer) which includes a head which jets a liquid from nozzles.
2. Description of the Related Art
As a typical example of a liquid droplet jetting apparatus, an ink-jet printer which includes an ink supply channel which supplies an ink to a head, and a mounting portion on which a cartridge-type main tank storing the ink is mounted detachably, has hitherto been known widely. When the main tank is mounted on the mounting portion, the ink in the main tank is supplied to the head via the ink supply channel.
In a case of replacing the main tank by a new main tank when the ink in the ink tank has run down, there is a possibility that air enters the ink supply channel. To cope with this, an ink-jet printer provided with a sub tank (buffer tank) which is open to the atmosphere between the head and the ink supply channel so that air does not enter the ink supply channel even when the ink in the ink cartridge has run down has hitherto been known (Japanese Patent Application Laid-open Publication No. 2005-66906). An atmosphere opening hole, which makes an internal space storing the ink, communicate with the atmosphere is formed in the sub tank. According to such structure, even when the ink in the ink tank has run down, the air does not enter into the ink supply tube (channel) because the ink is remained in the sub tank. Furthermore, even when the air enters into a connecting portion between the main tank and the sub tank at the time of replacing the main tank, the air is separated from the ink by buoyancy (buoyant force) in the sub tank. Therefore, the entry of the air into the ink supply channel is prevented.
In the invention described in Japanese Patent Application Laid-open No. 2005-66906, a communicating hole which communicates with an ink cartridge is provided in a ceiling portion of the sub tank, and the ink cartridge is mounted in a perpendicular direction. Consequently, even when the ink cartridge removed, since the communicating hole is positioned above a level of the ink, the ink filled in the sub tank is not leaked from (through) the communicating hole.
On the other hand, an ink-jet printer in which the ink-jet cartridge is mounted from a horizontal direction (slid horizontally from a side) has also been proposed, and is in accordance with the preference and liking for operability and design of users.